President Obama's vision of a clean energy future of wind farms and solar plants comes with a catch: It will require thousands of miles of new high-voltage power lines to move the energy from where it's most abundant, in the California desert or the plains of the Midwest, to power-hungry urban centers.

Obama's allies in Congress, including House Speaker Nancy Pelosi, D-San Francisco, and Senate Majority Leader Harry Reid, D-Nev., are pushing legislation that would give federal officials new authority to site those lines if states don't act quickly enough to expand the grid.

The plan is raising concerns among state regulators, who see an intrusion on states' rights, and property rights advocates, who fear an increased use of eminent domain to build the lines across private lands. The proposal is dividing environmentalists, who are torn between the need to connect to cleaner energy sources and fears the projects could endanger sensitive species.

The legislation could have far-reaching effects in California, which has vast solar resources, especially in the Mojave Desert. Gov. Arnold Schwarzenegger signed an order last fall requiring the state to get 33 percent of its energy from renewable sources by 2020, adding pressure to expand transmission lines.

Advocates of Reid's proposal say speed is essential to avoid yearslong delays in building the lines and to get renewable power online quickly to fight global warming. Some lines will crisscross states - delivering wind energy from North Dakota to Minneapolis and Chicago - which will require cost-sharing and planning that may be difficult without federal help.

"Many states have already begun to adopt innovative policies to move toward more clean, efficient transmission systems," Pelosi said at an energy summit last month. "But what we need is a national framework for planning, developing and financing transmission infrastructure."

Reid, whose home state of Nevada is already seeing a boom in solar projects, has crafted a bill requiring the administration to create "renewable energy zones" in places where wind, solar and geothermal energy is most plentiful. States would have to devise plans for where to site new transmission corridors and who would pay for them within a year or the Federal Energy Regulatory Commission could step in and draw the lines.

"We cannot let 231 state regulators hold up progress," he said. "They should be given every opportunity to see if we can work this out through the state regulators. If that can't be done, I think there are very few alternatives for the American people."

Property rights activists also fear federal officials will expand the use of eminent domain to force landowners to accept high-voltage lines on their farms, businesses or backyards. "We believe that private property owners have every right to say no to transmission lines on their land," said Sen. John Barrasso, R-Wyo.

Overriding states

Congress, in the 2005 Energy Policy Act, gave FERC the power to override states and designate "National Interest Electric Transmission Corridors," after the Northeast blackout of 2003. But the agency's authority was challenged recently when the Fourth U.S. Circuit Court of Appeals in Virginia ruled the agency could issue a permit if the state failed to act within a year, but could not overrule a state's decision.

California officials have been trying to speed up the permitting process for new transmission lines. But the projects are still highly controversial: San Diego Gas & Electric drew an outcry when it first proposed building a 150-mile line through California's largest state park, the Anza-Borrego Desert State Park. The utility has changed the route, but it is still waiting for final approval from regulators and the plan is likely to face court challenges.

Many locals complain the lines are unsightly and could heighten the risk of wildfires. Some environmentalists believe a better model is small-scale solar - rooftop projects or small solar plants built near cities - to avoid the need for new power lines.

"We're asking the wrong question when we ask about siting new transmission for renewables before we ask what can be saved with less consumption, greater efficiency of the current grid and locally distributed energy," said Ruth Rieman, vice chair of the California Desert Coalition.

"The goal is not to pick places that are going to be controversial," said Carl Zichella, who oversees transmission issues for the Sierra Club. "We are all working together to figure out how to get this power to market quickly so it reaches consumers in a time frame that helps us deal with global warming."

BrightSource Energy, an Oakland developer of solar thermal plants, is trying to limit those conflicts by building near existing transmission lines. Its first big project, the Ivanpah complex in the Mojave Desert near the California-Nevada border, which would power 250,000 homes, has power lines that run through it.

"There's going to be an impact" on the environment, said BrightSource spokesman Keely Wachs. "The question is how you can minimize it."

Reid said he hopes to bring his transmission plan to the Senate floor this summer as part of a massive energy and climate package that would also include a requirement that states boost their use of renewable energy as well as cap-and-trade legislation to limit greenhouse gas. It's a huge gamble - all three bills have major opposition - but it would force lawmakers to cast an up-or-down vote on Obama's effort to remake the nation's energy system.